Renewable filter with a bypass valve

ABSTRACT

A twist-on renewable filter comprising a one-piece hollow housing, made of polymeric material having a threaded adapter for attachment to a distribution head assembly. The filter housing is fabricated from components that are made of a polymeric material that are fused together to form the one-piece hollow housing. A filter media assembly is rigidly bonded at both ends within the housing. The renewable filter has an infinite life and can be removed and cleaned, for example, by reverse flushing the filter with a cleaning solution. A bypass valve 250 is provided within the filter that is designed to provide full closure for an infinite life. The bypass valve 250 is fully located within the one-piece hollow housing such that it cannot be disabled or tampered with. The bypass valve 250 functions to allow sufficient fluid to bypass the filter media when the filter media has become contaminated and will not permit the full volume of the normal oil stream to be filtered. The bypass valve 250 has the capacity to permit the full volume of the normal oil stream to bypass the filter media when necessary, for example, during a cold start.

RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.09/373,438 filed on Aug. 11, 1999, now U.S. Pat. No. 6,221,242, which isa continuation-in-part of U.S. patent application Ser. No. 08/951,387filed on Oct. 16, 1997, now U.S. Pat. No. 6,228,274, which claims thebenefit of U.S. provisional application Ser. No. 60/033,387 filed onDec. 17, 1996.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to filtering devices. Inparticular, the present invention relates to a renewable spin-on typefilter having a high strength plastic housing.

2. Discussion of Background

Spin-on, twist-on type filters are used in numerous liquid and pneumaticapplications throughout the agricultural, transportation, commercial andindustrial markets. The housing or can for most spin-on disposablefilters are manufactured from malleable materials, such as aluminum by adeep-draw forming process. This technique limits the structuralcapabilities of current spin-on and twist-on type disposable products tothe production capabilities of the metal forming industry and to themolecular characteristics of a limited number of specific malleablemetals. Prior art disposable filters use stamped steel or cast coverplates to secure the housing or can to a mounting and distribution headassembly. This plate typically has a threaded center hole and isspot-welded and/or crimp-sealed to a deep drawn can. The purpose of thecover plate is to provide a mounting section that contains sufficientstrength to allow operation of the filter at the required pressurerating. These prior art techniques for sealing and connecting the can tothe plate, plus the structural limits of thin gauge malleable metals,restrict the application and uses of prior art spin-on, twist-ondisposable filters. Recently, new high pressure, high burst strengthdisposable filter housings with burst pressure ratings in the 1000 psirange have been developed for some narrowly defined markets andapplications. However, even these newer, high-strength filters remainapplicationally limited because of their continued use of deep-drawnmetal cans.

The filter media used in the prior art are usually paper products thatare flexible and flimsy. As a result of their flexible and flimsycharacteristics, these filters often are not properly secured in placewithin the housing or can during the assembly of the filter. By someaccounts, 50% of current commercially available oil filters aredefective and thus do not perform up to specification. Also, prior artpaper filters often develop rips or tears during use. For example, ifthere is a spike in the pressure of the fluid being filtered, paperfilters will often develop a rip through which unfiltered fluid flows.Such rips generally increase in size as a result of the rush of fluidflow there through. Such defects are not visible and unknown to themachine operator and the use of the filter continued for its normal useperiod during which improperly filtered oil is re-circulated through themachine or engine. Serious damage to the machine or engine can result.Once these disposable filters have been severed, they can no longerserve their purpose and should be replaced.

When conventional filters reach the end of their useful life, the filteris removed from the vehicle or machine and the remaining filtrate,usually oil, is drained and a new filter is installed. Thereafter, thefilter should be compacted and disposed of in accordance with industrypractice. However, often the used filter is disposed of in a way that itis eventually placed in a land fill. The impact on the environment fromthe disposal of used filters and oil is devastating to the environment.The enormity of this problem is realized when the variety of industrialand consumer applications that employ disposable filters, as well as thefrequency with which these filters are replaced, is considered. Theimpact on the environment can be appreciated when it is realized thatthere are currently about 180,000,000 vehicles in the United States forwhich it is recommend that the filter and oil be changed every 3,000miles. About 400,000,000 oil filters are manufactured in the U.S. eachyear, of which less than 25% are properly recycled. The remaining, whichretain some oil, are disposed of and this used oil enters theenvironment. Even properly drained oil filters can retain up to 8 ouncesof used oil. It is estimated that the result of proper recycling wouldresult in the recovery of more than 17,000,000 gallons of oil. Ifproperly processed, this oil could be reused.

Therefore, there exists a need for a twist-on filter that is renewablewhich would support and encourage the recycling of used oil and reduceenvironmental liability.

If an oil filter is not serviced, it can become clogged and the flow ofincoming oil will be impeded and eventually completely stop from passingthrough the filtering media. When the filter becomes blocked withcontaminates, fluid flow is restricted and diminished and thedifferential pressure across the filter element increases. As the volumeof the flow diminishes, parts of the machine or engine that normallyreceive lubrication will receive inadequate lubrication. The typicallubrication systems for an internal combustion engine pump oil from asump through a loop, splashing oil over and around moving engine parts,such as the valves and piston rods. The oil filter is a componentthrough which the oil flows in this oil flow loop. Thus, if the oilfilter becomes clogged, the flow of oil is impeded and lubricationbecomes inadequate. However, the damage to an engine or machine will beless if the circulation of the contaminated oil is continued rather thanallowing the circulation of oil to be stopped. Thus, it is importantthat a bypass be provided to allow the circulation of oil to continuewhen it cannot pass through the filter media. Also, when an engine thatis in a cold environment is started, the viscosity of the crankcase oilis very high and resists being forced through the filter media. It isimportant, in such situations, that provisions are available to allowthe oil to bypass the filter for a period while its temperatureincreases and its viscosity decreases. For these reasons, oil filtersshould have a bypass system to protect the engine in the event of aclogged filter. Bypass valves for oil filters are known. However, theyare complicated, expensive and are not an integral part of the filter.There is a need for a filter device that has a simple mechanical bypassthat is an integral part of the filter device and cannot be disconnectedor tampered with

A typical automotive poppet type bypass valve has a very limited surfacearea against which the liquid that is at an elevated pressure must reactto cause the bypass valve to open. This renders the valve unreliable forits intended purpose. Also, the typical automotive poppet type bypassvalve utilizes a compression spring to urge the valve closed.Compression springs are very vulnerable to premature fatigue failure.The filter of this invention has an infinite life and, thus, if thefilter of this invention is provided, a built-in bypass valve shouldalso have an infinite life. Another shortfall of the typical automotivetype poppet bypass valve of the type that relies on a compression springto return the valve to its closed position is that it is unlikely thatfull closure will be attained. Coil type compression springs are roundedon both ends and cannot be properly guided. As a result, compressionsprings take the path of least resistance when they expand. Furthermore,coil type compression springs do not exert an equal pressure over thelength of their expansion and, thus, do not provide a uniform pressureon the poppet valve.

Accordingly, there is a need for a simple bypass valve that is builtinto a renewable filter that has an infinite life cycle to match thelife cycle of the renewable filter. There is also a need for a filterhaving a bypass valve that has a relatively large surface against whichthe liquid at elevated pressure reacts to increase the reliability ofthe valve. Still further, there is a need for a filter having a bypassvalve that does not rely upon a coil type compression spring to closethe valve. There is also a need for a renewable filter having anintegral bypass valve that, when fully open, has the capacity to bypassthe full volume of the normal oil flow.

SUMMARY OF THE INVENTION

According to its major aspects and briefly stated, the present inventionis a renewable twist-on filter that is made from a sealed polymeric,unitary housing that has a filter media assembly securely bonded inplace within the interior of the housing. After a use period that can bemeasured either in elapsed time or, for automotive uses, in milestraveled, the filter will be removed and replaced. The filter that hasbeen removed will then be cleaned, after which it is put back intocirculation for another use period. The filter housing is plastic weldedtogether and, thus, would be destroyed if it is opened or tampered with.The filter is designed to last for an unlimited time and is designed towithstand pressures in excess of three times the normal operatingpressure that it is expected to be exposed to. In one embodiment of theinvention, a bypass valve is built into the interior of the housing toallow circulation of the fluid to continue in the event, for example,that the filter becomes contaminated or in the event of a cold start.The filter housing carries a metallic adapter having machined threadsfor securing the filter housing to an engine or machine. Adapters canhave internal or external threads and be of various sizes and threadtypes. It is also contemplated that this adapter could be formed ofplastic material.

The housing formed from a hollow polymeric container. In a preferredembodiment, there is a polymeric container member having an open top anda polymeric top member that are plastic welded together to thus providea closed housing having an interior chamber. The filter media isfabricated from multiple layers of metal mesh material and, thus, is arigid stable item which assures that, in the assembly process, it isproperly located. During the assembly process, the filter media isbonded in place within the interior chamber and its position within thechamber is assured by plastic welding of the container member to the topmember. The assembly procedure guarantees the initial proper location ofthe filter media assembly and the plastic welding assures that thislocation will be maintained. Thus, the top member is fused to the hollowpolymeric container and this assembly now functions as a closed housinghaving an interior chamber within which is securely attached the filtermedia assembly. It should be noted that, although the preferredembodiment discloses a housing formed from a cup-shaped member that isclosed by a disc-shaped top member, the top member need not bedisc-shaped but rather could also be cup-shaped. It should also be notedthat, although the hollow polymeric container or cup-shaped member isdisclosed as being a unitary cast part, it could also be fabricated froma section of polymeric tube having a molded bottom end member bonded orwelded thereto. The essential feature being that the components fromwhich the hollow housing are formed are welded together to form a closedhousing having an interior chamber within which is securely attached thefilter media assembly. The filter media assembly is secured by adhesiveat both ends within the housing such that the filter media assembly isimmovable relative to the housing. The bottom of the filter mediaassembly is secured to the bottom or closed interior end of the housingby an adhesive material. The top of the filter media assembly is alsobonded to a media collector plate that is connected to the inner surfaceof the top member. The filter media assembly divides the interiorchamber of the housing into an inlet section and a discharge section.The filter media assembly could be any type that is commonly employed inthe art provided it is capable of being cleaned and subsequently reused.

The preferred embodiment of the filter media assembly formed from threelayers of metal mesh material. Each layer is cut to a shape having apair of edges that, when joined by a weld or encapsulated by adhesive,cause the flat piece of material to assume the shape of a cone. Themetal mesh material is folded or pleated radially such that, after theedges are joined, the filter is in the shape of a truncated cone havingcontinuous top and bottom edges. The pleats extend from the topcontinuous edge to the bottom continuous edge. The surface area of thefilter media assembly is greatly increased by such a filter design. Theinner and outer metal mesh material layers are formed of relativelylarge stainless steel wire and have relatively large openings. Theselayers of metal mesh function mainly as supports and protection for thecentral layer which formed from much smaller wires and has very smallfiltering openings. An important function performed by the heavy gaugeinner and outer layers is to assure that the pleats of the central layerdo not collapse upon each other to form a double layer.

When the filter requires cleaning, it is removed from the distributionhead of the vehicle or machine, and the excess fluid contained thereinis drained out. This small amount of drained fluid can be easilydisposed of in a manner that is not detrimental to the environment.Thereafter, the filter is back flushed using a cleaning solution. Oncecleaned, the filter may be dried prior to reuse by allowing it to standfor a period of time or by blowing a drying gas therethrough. As aresult of using the highly efficient and reliable filter, it is notnecessary to change the oil each time the filter is cleaned. Testvehicles have currently exceeded 12,000 miles without an oil change andtest of the oil shows little deterioration.

A major feature of the present invention is the unitary design of thepolymeric housing.

Still another feature of the present invention is the combination of apolymeric housing and a renewable filter media assembly. Thiscombination enables the filter to be cleaned and recycled which, inturn, significantly reduces the deleterious impact on the environment.

Another significant feature of this invention is the provision of afilter that has been provided having a bypass valve within the confinesof the filter that requires no external conduits or accessories. Thisbypass valve, like the filter, has been designed for an infinite lifecycle. The closure member for the bypass valve is maintained in aprecise disposition as it is compressed as a result of it being guidedby the outer surface of a brass adapter. This assures a full closure ofthe valve. Applicant's stainless steel spring engages the closure memberat a plurality of equally spaced locations to exert a force on theclosure member causing it to slide smoothly without binding along thesmooth outer annular surface of the threaded adapter. As a resultapplicant's bypass valve will always return to its full closed position.The closure member of the bypass valve has a reaction surface area thatis sufficient to insure that when fully open the bypass valve canbypassing the full volume of the normal oil flow. This is particularlyimportant in cold start situations since it permits the full flow ofunfiltered oil.

Other features and their advantages will be apparent to those skilled inthe art from a careful reading of the detailed description of thepreferred embodiments accompanied by the following drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a perspective view of an embodiment of the present invention;

FIG. 2 is a cross-sectional side view of the embodiment of the presentinvention taken along lines 2—2 of FIG. 1;

FIG. 3 is a perspective view of another embodiment of the presentinvention;

FIG. 4 is a cross-section view of the embodiment of the presentinvention taken along lines 4—4 of FIG. 3;

FIG. 5 is a cross-section view of the embodiment of the presentinvention taken along lines 5—5 of FIG. 3;

FIG. 6 is a top view of the embodiment of the present invention seen inFIG. 3;

FIG. 7 is an enlarged cross-section view of the embodiment seen in FIG.3 of the top member at a location spaced above the hollow polymericcontainer;

FIG. 8 is an enlarged cross-section view of a portion of the top memberat a location spaced above the hollow polymeric container showinganother embodiment of the connection between the top member and thehollow polymeric container;

FIG. 9 is a top view of the top member for the preferred embodiment;

FIG. 10 is a bottom view of the top member for the preferred embodiment;

FIG. 11 is a cross-section view of the preferred embodiment; and

FIG. 12 is an exploded view of parts of the bypass valve of thepreferred embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention provides a renewable, spin-on type tube filterdesigned to remove contaminates from a lubricant or other industrialfluid. The filter media assembly advanced by the present invention issuitable for use in a wide variety of industrial applications. Referringnow to FIGS. 1 and 2, there is shown a perspective view and across-sectional view, respectively, of a filter according to oneembodiment of the present invention and generally designated byreference numeral 10. Filter 10 is comprised of a hollow housing 20having a top end portion including a top member 50 and a bottom endportion. The hollow housing 20 has an interior chamber that is dividedby filter media assembly element 40 into an inlet section and adischarge section. Housing 20 comprises a hollow polymeric container 60having a bottom or closed-end 26 and an open-end 22. Inner wall 21,floor or bottom surface 44 and the internal surface of top member 50define the interior chamber 42 of hollow housing 20.

An external thread 28 formed about the perimeter of hollow polymericcontainer 60 proximate to open-end 22. Thread 28 may be manufactured toany size which, in turn, enables filter 10 to achieve the specificpressure rating required by the particular application. Thread 28 formedto removably mate with a variety of distribution heads commonly used inindustry thereby enabling filter 10 to be employed in a variety ofindustrial applications.

Hollow polymeric container 60 is made of any polymeric material that canoperate in a temperature range between approximately −40° C. and 190° C.without experiencing thermal degradation. Hollow polymeric container 60can be formed to assume any thickness and length. The dimensions ofhollow polymeric container 50 are selected to provide a stable structureat its intended operating temperature and pressure. Preferably, hollowpolymeric container 60 is made of a polymeric material impregnated witha quantity of glass fibers. Extending from the bottom or closed-end 26about the perimeter of hollow polymeric container 60 is a series ofserrations 30 designed to permit an individual to grasp housing 20.Formed about the perimeter of bottom or closed-end 26 is an annulargroove 32. A circular recess 34 formed at the center of bottom orclosed-end 26.

Extending into the interior 42 of hollow polymeric container 60 fromfloor 44 is an annular shoulder 36. Shoulder 36 is dimensioned to fitwithin the annular center 46 defined by filter element 40. Shoulder 36serves to center filter element 40 within interior 42 of hollowpolymeric container 60. As best seen in FIG. 2, the peripheral edge oftop member 50 is spaced from the inner wall 21 of the hollow polymericcontainer 60 which defines an annular opening that functions as theindustrial fluid outlet 58. Filter element 40 may be fabricated of anyfilter medium commonly employed in the art including, but not limitedto, stainless steel mesh, polyesters and cellulosic materials. The meshor porosity of the filter media 40 is determined by industrial fluid andoperating conditions to which they will be exposed. The stiffness of thefilter must be sufficient such that it maintains its geometric integrityand will not flex or deform when exposed to normal operating conditionsand/or to back flushing. Filter element 40 has an inlet surface 45 thatis in fluid communication with the throughhole or industrial fluid inlet52 and an outer or outlet surface 43 that is in fluid communication withthe industrial fluid outlet 58. If filter 40 is constructed of bendableor flexible material, a perforated annular core, made of metal orpolymer, may be required so that filter element 40 maintains itsgeometric integrity. Filter element 40 is tubular and has an endlessbottom or closed-end portion edge 47 and an endless top or open-endportion edge 41. The filter element 40 is secured along its bottom orclosed-end portion edge 47 to floor 44 by an adhesive, potting orbonding material 48. The filter element 40 is secured along its top oropen-end portion edge 41 in an annular groove 33 formed in the bottomsurface of top member 50 using bonding material 48. The annular groove33 is located between the industrial fluid inlet 52 formed in top member50 and the industrial fluid outlet 58 formed by the peripheral edge oftop member 50 and inner wall 21 of the hollow polymeric container 60and, thus, isolates the industrial fluid inlet 52 from the industrialfluid outlet 58. As a consequence of this isolation, the industrialfluid that enters the inlet chamber of filter 10 through the industrialfluid inlet 52 must pass through the filter element 40 to reach thedischarge section that is in fluid communication with industrial fluidoutlet 58. Bonding material 48 may be any type commonly employed in theart that will not react with the fluid being filtered and can withstandoperating temperatures between approximately −40° C. and 190° C.

In the embodiment illustrated in FIGS. 1 and 2, top member 50 may bemade of either a metal or polymer and formed to have a throughhole orindustrial fluid inlet 52 in registration with annular center 46 offilter element 40. An O-ring 54 is provided in industrial fluid inlet 52that functions as a fluid seal between throughhole or industrial fluidinlet 52 and the distribution head.

Hollow polymeric container 60 can be manufactured using any processcommonly employed in the art. Preferably, housing 20 is manufacturedusing an injection molding process. In assembling filter 10, filterelement 40 is secured to top member 50 using bonding material 48.Bonding material 48 is then applied to floor 44 of hollow polymericcontainer 60. Filter element 40 and top member 50 are then placed withininterior 42 of hollow polymeric container 60 and secured to floor 44.

When filter 10 requires cleaning, it is removed from the distributionhead and the excess lubricant is drained. Thereafter, a cleaningsolution is injected into housing 20 in the direction opposite to thedirection of filtration. For example, cleaning solution may be directedthrough industrial fluid outlet 58 into annulus 56 which is defined byouter surface 43 of filter element 40 and the inner wall 21 of hollowpolymeric container 60. The injection of solution into annulus 56effectuates the removal of particulates from filter element 40 andtransports the fluid entrained particles into annular center 46 andsubsequently from the interior 42 of hollow polymeric container 60.Alternatively, cleaning solution may be injected through industrialfluid inlet 52 into annular center 46 to thereby cause the removal ofparticulates from filter element 40 through annulus 56 and industrialfluid outlet 58 to the exterior of housing 20. An ultrasonic cleaningmethod could also be used for cleaning the filters 10. After cleaning,filter 10 is dried and reused.

Referring now to FIGS. 3-8 another embodiment of the present inventionwill be discussed. FIG. 3 is a perspective view of a filter according tothis embodiment of the present invention and is generally designated byreference numeral 100. Filter 100 is comprised of a hollow housing 120having a top-end portion, including top member 150, and a bottom-endportion 160. Cup-shaped bottom-end portion 160 and top member 150 aremade of any polymeric material that can operate in a temperature rangebetween approximately −40° C. and 190° C. without experiencing thermaldegradation. In the preferred embodiment top member 150 and thebottom-end portion 160 are formed by an injection molding process usinglong fiber polymer composite reinforced thermoplastic material that issold under the brand name CELSTRAN®. CELSTRAN® is a registered trademarkof Hoechst Celanese Corporation. Cup-shaped bottom-end portion 160 canbe formed to assume any thickness and length. It should be noted that,although this embodiment discloses a housing formed from a cup-shapedbottom-end portion 160 that is closed by a disc-shaped top member 150,the top member need not be disc-shaped but rather could be a cup-shapedtop member. It should also be noted that, although the hollow polymericcontainer or cup 160 shaped member is disclosed as being a unitary castpart, it could also be fabricated from a section of polymeric tubehaving a molded bottom member bonded or welded thereto. The essentialfeature being that the components from which the hollow housing 120 areformed are welded together to form a closed-housing having an interiorchamber 142 within which is securely attached the filter media assembly140. As best seen in FIGS. 4 and 5, which are cross-section views takenalong lines 4—4 and 5—5, respectively, of FIG. 4, housing 120 has aninterior chamber that is divided into an inlet section 162 and adischarge section 164 by filter media assembly 140. The filter mediaassembly 140 is securely mounted within the housing. The cup-shapedbottom-end portion has a bottom or closed-end 126 and an open or top-end122. Cup-shaped bottom-end portion 160 has an interior 142 that isdefined by inner wall 121 and a floor or bottom surface 144.

Filter media assembly 140 has a frusta-conical shape and has an endlessbottom or closed-end portion edge 147 and an endless top or open-endportion edge 141. The illustration of the multi-layered filter mediaassembly 140 is shown schematically in FIG. 4 to clearly illustrate thatthe filter assembly is comprised of multiple layers. In this schematicrendering, the layers are shown spaced apart from each other while inreality the layers are engaged. The filter media assembly 140 is securedalong its bottom or closed-end portion edge 147 in an annular groove 136formed in floor 144 by an adhesive bonding material 148. The filtermedia assembly 140 is secured along its top or open-end portion edge 141to a filter collector member 180 which, in the preferred embodiment, ismade by an injection molding process from long fiber reinforcedthermoplastic material sold under the brand name CELSTRAN®. Filtercollector member 180 is received in a circular groove formed in thebottom surface of top member 150. This arrangement facilitates assemblyof the filter 100 and, once assembled, the endless open-end portion edge141 of the filter media assembly 140 is, in effect, bonded along itsentire extent to the open-end top member 150. Filter collector member180 has a flat washer-shaped portion with at least one downwardextending flange 184 along its peripheral edges. The central flange 184forms a concentric central bore 183 that is sized to receive adapter154. The filter media assembly 140 is secured by an adhesive bondingmaterial 148 along its upper closed-end portion edge 141 in the annulargroove formed by the downward extending flanges 184 of collector member180. Filter media assembly 140 isolates the industrial fluid outlet 153from the industrial fluid inlet 158. As a consequence of this isolation,the industrial fluid that enters the inlet section 162 of filter 100through the industrial fluid inlet 158 must pass through the filtermedia assembly 140 to reach the discharge section 164 from which it isdischarged through industrial fluid outlet 153.

As illustrated in FIG. 6, which is a top view of filter 100, industrialfluid inlet 158 includes four openings 158 that are concentric withcentral bore 152. The four openings 158 are separated by bridges 159.The top member 150 includes a circular groove 157 formed in its upper orouter surface that receives a mating O-ring or other seal that functionsto form a seal between the top member 150 and the distribution head (notshown). A distribution head 200 is shown in FIG. 11. The O-ring or otherseal is contained in the circular groove, 157 to assure a liquid sealbetween the top member 150 and the distribution head.

As is best seen in FIG. 7, the inner wall 121 of cup-shaped bottom-endportion 160 has a recessed rim 124 formed along its upper edge that hasa larger diameter than inner wall 121. The peripheral edge 151 of topmember 150 has a diameter that is slightly smaller than the diameter ofrecessed rim 124 and, thus, the top member 150 can be lowered into theopen-end of cup-shaped bottom-end portion 160 without interference. Aband 125 of polymeric material having a diameter smaller than recessedrim 124 and larger than inner wall 121 is provided as a step between thebottom of recessed rim 124 and the inner wall 121. During assembly ofthe filter 100, as the top member 150 is lowered into cup-shapedbottom-end portion 160, the bottom surface of top member 150 encountersband 125 which prevents top member 150 from becoming fully seated incup-shaped bottom-end portion 160. As will be discussed in more detail,this interference with band 125 will be overcome during the plasticwelding process that secures the top member 150 to the cup-shapedbottom-end portion 160. Thus, when assembly is complete, the top member150 will be fully seated in the open-end 122 of cup-shaped bottom-endportion 160, and member 150 and cup-shaped bottom-end portion 160 willhave been bonded together as an integral member. As shall be furtherdiscussed, top member 150 is permanently secured to cup-shapedbottom-end portion 160 by a plastic weld.

Another embodiment for the bonding of the peripheral edge of top member150 to the inner wall 121 of the cup-shaped bottom-end portion 160 isillustrated in FIG. 8. In this embodiment, the peripheral edge of topmember 150 has an upper section 255 that has the same diameter as theouter diameter of the cup-shaped bottom-end portion 160 and a lowersection 256 that is slightly smaller than the inner diameter of thecup-shaped bottom-end portion 160. This allows the lower section 256 oftop member 150 to enter the open, upper end of the cup-shaped bottom-endportion 160 without interference. The peripheral edge of top member 150includes a band portion 257 that has a diameter that is larger than thediameter of the lower section 256 and smaller than the diameter of theupper section 255. As the top member 150 is lowered into the cup-shapedbottom-end portion 160, the band portion 257 will encounter the upperedge of the cup-shaped bottom-end portion 160 and prevent the top member150 from fully seating. At this point of the fabrication, the ultrasonicwelding operation commences which melts the material forming the bandportion 257 permitting the top member to completely seat in cup-shapedbottom-end portion 160 and form a bond therewith. This embodiment hasthe advantage that there will not be a resulting bead of weld on theupper surface of the top member 150 which could interfere with theattachment of the filter media assembly 100 to the distribution head.

An inner wall 121 and a floor 144 define the interior 142 of cup-shapedbottom-end portion 160. A circular groove 136 formed in floor 144.Groove 136, as illustrated in FIG. 4, is located at the intersection ofwall 121 and floor 144 but could be spaced centrally of thisintersection. Groove 136 serves to receive the lower or bottom edge 147of the filter media assembly 140. Filter media assembly 140 may befabricated of any filter medium commonly employed in the art, includingbut not limited to, stainless steel mesh, polyesters, or cellulosematerials. Filter media assembly 140 has an outer screen 143 that is influid communication with the industrial fluid inlet 158 and an innerscreen 145 that is in fluid communication with the industrial fluidoutlet 153.

The filter media assembly 140 that is illustrated in FIGS. 4 and 5 andalso in FIG. 11 formed from flat material that has been cut to a shapethat includes a pair of edges. This discussion of the filter mediaassembly 140 applies equally to the embodiment, illustrated in FIGS.3-8, as well as the embodiment illustrated in FIGS. 9-12. When the pairof edges are joined by a weld or encapsulated by adhesive, the flatpiece of material assumes the shape of a cone. In the preferredembodiment, the material is stainless steel wire mesh which provides afilter media assembly that is stiff and will not be distorted or bent byfluid flow through it. The metal mesh material is folded or pleatedradially such that the filter is in the shape of a truncated cone havingwave-shaped continuous top and bottom edges. The radial pleats extendfrom the upper peripheral edge to the lower peripheral edge of the rightcircular cone-shaped filter. The pleats are formed such that theiramplitude becomes greater as they progress from the upper periphery edgeto the lower peripheral edge. As a result of forming these pleats andjoining the edges, the flat pieces of material from which filter mediaassembly 140 formed assumes the shape of a frustum of a right circularcone. The surface area and, thus, the filtering capacity of the filtermedia assembly 140 are greatly increased as a result of the pleats.Furthermore, the rigidity and therefore the geometric integrity of thefilter media assembly 140 are increased considerably as a result of thepleats. The filter media assembly illustrated in FIGS. 4 and 5 iscomprised of three layers of woven mesh screens. The outer screen 143and the inner screen 145 have a wire count of 40 to 60 wires per inch.The preferred embodiment of the outer 143 and inner 145 screens have 50stainless steel wires per inch. These relatively sturdy, woven meshouter screens function to provide structural integrity to the filtermedia and also to insure pleat separation of the middle, woven meshscreen 146 to avoid the pleats from compressing upon themselves. Theopenings in the inner and outer, woven mesh screens are much larger thanthe openings of the middle, woven mesh screen 146 and as a result themiddle, woven mesh screen defines the porosity of the filter mediaassembly. The size of the openings in the middle mesh screen 146, forthe preferred embodiment, are 25 microns. This mesh screen has a 47%porosity which means that 47% of its surface is open. Mesh screen 146will retain particles that are larger than about 25 microns. Applicanthas also used middle screens 146 that have openings of about 17 microns.The 17 micron screen has a porosity of 37%. The openings in the middlemesh screen 146 must be very small in the range of 15-30 microns. Thus,the middle layer of filter media assembly 140 functions as the filteringlayer, and the inner layers 145 and outer layers 143 function to providestructural integrity and to insure pleat separation of the middle layer.

In the assembly process, the upper edge 141 of filter media assembly 140is secured to the lower surface of disc-shaped filter mounting plate 180using bonding material 148. Bonding material 148 is then place in groove136 formed in floor 144. The filter media assembly with the attacheddisc-shaped filter mounting plate 180 is then lowered into thecup-shaped bottom-end portion 160. The large or lower peripheral edge147 of filter media assembly 140 approaches the groove 136 that containsbonding material 148.

The top member 150 is then lowered into the open-end 122 of thecup-shaped bottom-end portion 160 and the adapter 154 enters the centralaperture 183 of the mounting plate 180. As the top member 150 is loweredinto the cup-shaped bottom-end portion 160, the band 125 (see FIG. 7) ofpolymeric material engages the bottom surface of top member 150. The topmember 150 has been manufactured such that the diameter of itsperipheral edge 151 is slightly smaller than the diameter of the rim 124of the cup-shaped bottom-end portion 160. The top member 150 and the topend 122 of the cup-shaped bottom-end portion 160 is then subjected to anultrasonic welder which melts the band 125 of polymeric material whichenables the top member 150 to be forced downwardly into place in thecup-shaped bottom-end portion 160. The melted material of band 125 thenforms a bond with the rim 124 of the inner wall 121 and the peripheraledge 138 of top member 150. During the ultrasonic welding, the raisedconcentric annulus of the upper surface of filter mounting plate 180enters the open bottom of the chamber and closes the chamber. As aresult, the top member 150 has been permanently secured to thecup-shaped bottom-end portion 160 to form the housing 120. Anotherresult is that the bottom edge of filter media assembly 140 has beenpermanently secured in the groove 136 and the collector plate 180 hasbeen joined to the top member 150 as an integral part thereof. Since thetop edge of filter media assembly 140 is bonded to the collector plate180 when assembled, the top edge of filter media assembly 140 is bondedto the top member 150. Consequently, after assembly is completed, therecan be no relative movement of filter media assembly 140 relative to thehousing 120.

It should be noted that, although the filter media assembly 140 that isshaped as a right circular cone is preferred, filters having othershapes, for example tubular, could be used with this invention.

The large or bottom peripheral edge 147 of filter media assembly 140 issecured in groove 136 formed in floor 144 by an adhesive bondingmaterial 148. This bonding permanently secures the lower edge 147 of thefilter media assembly 140 to the cup-shaped bottom-end portion 160 suchthat there can be no relative movement therebetween.

The disc-shaped filter mounting plate 180 includes annular flanges 184that extend downwardly from its peripheral edges. The upper peripheraledge 141 of the filter media assembly 140 is secured by epoxy bondingmaterial 148 in the circular groove formed by flanges 184 of thedisc-shaped filter mounting plate 180. When assembled, this bondingpermanently secures the upper edge of the filter 140 to the top member150 through the filter mounting plate 180 such that there can be norelative movement therebetween. Preferably, bonding material 148 is anepoxy resin.

The bonding material 148 used in the preferred embodiment is a one-partepoxy resin. Two part epoxy resins must be used soon after the two partsare combined which, in a production process as used in the manufactureof these filters, would require the continuous preparation of newbatches. One part epoxy resin takes longer to set and, thus, a batch canbe used for longer production runs. Another advantage in this particularapplication of a one-part epoxy resin is, since the one-part epoxy resintakes longer to set, it has time to settle to a smooth upper surfacethat does not have cracks and crevasses that can trap contaminates. Aone-part epoxy resin sold under the trade name ECCOBOND A-304 isavailable from Emerson and Cuming Specialty Polymers, a division ofNational Starch and Chemicals.

In the process of producing the parts that make up the filter 100,cup-shaped bottom-end portion 160, top member 150 and disc-shaped filtermounting plate 180 are manufactured using any process commonly employedin the art. Preferably, cup-shaped bottom-end portion 160, top member150 and disc-shaped filter mounting plate 180 are manufactured by aninjection molding process using long fiber polymer composite reinforcedthermoplastic materials such as CELSTRAN®.

Ultrasonic plastic welding is the preferred plastic welding process. Anultrasonic plastic welding apparatus has one or more sonic horns. Eachsonic horn has a generator-transducer for ultrasonically activating thehorn and its welding blades. When the sonic horn is activated,vibrations in the range of 20,000 cycles per second are createdproducing heat which melts the plastic material being welded. Afterdeactivation of the sonic horn, a permanent welded bond formed betweenthe top member 150 and the cup-shaped bottom-end portion 160. Thispermanent bond locks the filter media assembly 140 in place within thenow enclosed housing 120.

When filter 100 requires cleaning, it is removed from the distributionhead and the excess lubricant is drained from it. Thereafter, a cleaningsolution is injected into housing 120 in the direction opposite to thedirection of filtration. For example, cleaning solution is directed intooutlet 153. The injection of solution into outlet 153 effectuates theremoval of particulates from filter media assembly 140 and transportsthe fluid entrained particles into the inlet section 162 andsubsequently out fluid inlet 158. Alternatively, cleaning solution maybe injected into industrial fluid inlet 158 to thereby cause the removalof particulate from filter media assembly 140 through the outlet 153.After cleaning, filter 100 is dried and reused.

Referring now to FIGS. 9 through 12, the bypass valve 250 will bediscussed. The bypass valve 250 illustrated in FIGS. 9 through 12 couldbe incorporated into the embodiment of the filters discussed above. Thesame reference numbers will be used in the following discussion whenreferring to filter parts that are the same as those parts previouslydiscussed with reference to the embodiment of FIGS. 3-8.

As best seen in FIGS. 9 and 10, top and bottom views respectfully of thetop member 150, a circular bore 152 formed therein into which is securedan internally threaded metallic adapter 154. The internally threadedmetallic adapter 154 is secured in a central circular bore 152 formed intop member 150 by bonding material 148 or by plastic welding. If it isto be secured by plastic welding, then the outer surface of threadedmetallic adapter 154 is grooved or serrated to receive the liquidpolymeric material during welding and, thus, lock the threaded metallicadapter 154 in place. A variety of internally threaded adapters 154 areavailable having internal threads that are sized to mate with a varietyof distribution heads 200 commonly used in the industry, therebyenabling filter 100 to be employed in a variety of industrialapplications.

The distribution head 200, as best seen in FIG. 11, includes anexternally threaded conduit 202 that mates with the internally threadedadapter 154. The filtered fluid exits the filter 100 through theindustrial fluid outlet 153 from which it flows into conduit 202 of thedistribution head 200. Arrow 170, seen in FIG. 11, indicates thedirection that the industrial fluid flows as it exits filter 100. Thefluid to be filtered flows from conduit 204 of distribution head 200into filter 100 through the industrial fluid inlet 158 formed in topmember 150.

As best seen in FIG. 9, industrial fluid inlet 158 includes twelveopenings that are concentric with central bore 152. The twelve openingsare separated by bridges 159. As best seen in FIG. 11, top member 150includes a circular groove 157 formed in its upper or outer surface thatreceives a mating O-ring 240 or other seal that functions to form a sealbetween the top member 150 and the distribution head 200. The O-ring orother seal 240 is contained in the circular groove 157 to assure aliquid seal between the top member 150 and the distribution head 200.

A chamber 210 formed in top member 150 which is isolated from theindustrial fluid inlet 158 by wall 212 formed of the polymeric materialof the top member 150. Another wall of the chamber 210 is defined by theouter surface 155 of metal adapter 154. The chamber 210 has openings 214formed in the polymeric walls 212 that provide communication betweenchamber 210 and the industrial fluid inlet 158. A series of openings 156are formed through metal adapter 154 providing communication between theindustrial fluid outlet 153 and chamber 210. A spring-biased base plate220 having a central opening 221 and an annular shoulder 222 is locatedwithin chamber 210. Central opening 221 is sized to closely receiveadapter 154 and functions as a guide for the spring-biased base plate220. The annular shoulder 222 extends upward around the periphery of thebase plate 220 and terminates in a peripheral edge 224. Spring-biasedbase plate 220 functions as the opening and closing member for bypassvalve 250 and is guided during its opening and closing movement bysliding along its central opening 221 along the outer surface of metaladapter 154. This sliding arrangement of the spring-biased base plateenables its peripheral edge 224 to always lay in a plane that isparallel to the top surface of the chamber 212 and thus insure fullclosure of the bypass valve 250. When the spring-biased base plate 220is forced up by the spring 230, it slides along the outer surface 155 ofadapter 154 and is stopped when the peripheral edge 224 engages the topsurface of the chamber 210. Peripheral edge 224 engages the top wall ofchamber 210 outwardly of the openings 214 formed in the wall 212.Between the annular shoulder 222 and the central opening 221 there is aflat annulus 223 that has a substantial area. When the spring-biasedbase plate 220 is in the fully raised position, it functions toeffectively close the openings 214. The fluid to be filtered that entersthe filter 100 through the industrial fluid inlet 158 flows throughopenings 214 and exerts pressure on the flat annulus surface 223 of thespring-biased base plate 220. When the pressure on surface 223 exceedsthe upward pressure of the spring 230, the spring-biased base plate 220moves downwardly. As the central opening 221 in the spring-biased baseplate encounters the openings 156 formed in the adapter 154, inlet fluidflows through openings 156 into the industrial fluid outlet 153 and thusbypasses the filter media assembly 140. Since some inlet fluid may alsobe flowing through filter media assembly 140, the spring-biased baseplate 220 will move down only enough to allow the bypass of sufficientfluid to maintain the inlet pressure at a predetermined acceptablelevel. If the pressure of the inlet fluid is sufficiently high, thespring-biased base plate 220 will continue to move downward until theopenings 156 are fully open. When openings 156 are fully opened, theentire inlet oil stream can bypass the filter media assembly 140.

The polymeric wall 212 forming chamber 210 includes an annular portion226 that extends downward from the top surface of the chamber 210.Annular portion 226 is concentric with the outer surface of said metaladapter 154 and terminates in a peripheral edge 228. Peripheral edge 228is located at the level of the bottom surface of top member 150. Thebottom edge of metal adapter 154 extends downward beyond the bottomsurface of top member 150 and peripheral edge 228.

A disc-shaped filter mounting plate 180 is provided that has an uppersurface 181, a lower surface 182 and a central aperture 183 that issized to closely receive the outer surface of metal adapter 154. Theperipheral edge 228 of the annular portion 226 engages the upper surface181 of disc-shaped filter mounting plate 180. Thus, disc-shaped filtermounting plate 180 functions as the bottom surface of chamber 210.

The upper surface 181 of collector member 180 has a raised concentricannulus 185 around the central bore 183 that seats in the chamber 210formed by the polymeric walls 212 of top member 150. The filter mediaassembly 140 is secured by an adhesive bonding material 148 along itsbottom or closed-end portion edge 147 to annular groove 136 formed inthe floor 144. When the filter collecting member 180 is seated inchamber 210, its lower surface 182, defined by the downward extendingflange 184 and central aperture 183, is located between the industrialfluid outlet 153 and inlet 158 both formed in top member 150. Whenfilter media assembly 140 is secured in place within filter 100 itisolates the industrial fluid outlet 153 from the industrial fluid inlet158. As a consequence of this isolation, the industrial fluid thatenters the inlet section 162 of filter 100 through the industrial fluidinlet 158 must pass through the filter media assembly 140 to reach thedischarge section 164 from which it is discharged through industrialfluid outlet 153.

Wave type spring member 230 is washer-shaped and has axially radiatinghigh ridges 232 and low ridges 234 extending around its periphery. Thehigh ridges 232 engage the bottom surface of the spring-biased baseplate 220 and the low ridges 234 support the spring member 230 on theupper surface of the raised concentric annulus 185 of the filtercollector member 180. Spring 230 is generally in the form of a Belvillewasher, a device commonly used as a thrust element, the structure andfunction of which will be readily appreciated by those skilled in theart. As incorporated into the immediate invention, wave spring member230 is sized such that, as the inlet pressure increases, it can compresswhich results in a slight increase in its diameter. Spring member 230exerts a uniform pressure on the spring-biased base plate 220 over thefull range of its expansion. This is important since spring-biased baseplate 220 functions as the opening and closing member for the bypassvalve 250.

It should be understood that the foregoing disclosure is illustrative ofthe broad inventive concepts comprehended by this invention and thatvarious other modifications and improvements may be made to theinvention without departing from the spirit of the disclosed concept.

What is claimed is:
 1. A renewable filter for filtering fluidscomprising: a housing; said housing comprising a hollow polymericcontainer having a closed-end and an open-end, said housing alsoincluding an open-end top member; said open-end top member beingdimensioned and shaped to close said open-end of said hollow polymericcontainer; said open-end top member having an industrial fluid inletformed therein through which industrial fluid to be filtered enters saidhousing; said open-end top member having an industrial fluid outletformed therewith through which filtered industrial fluid exits saidhousing; said open-end top member having an annular groove formed in alower surface thereof and Positioned radially between said industrialfluid inlet and said industrial fluid outlet; a corrugated filterelement disposed within said hollow polymeric container, said filterelement having an inlet surface that is in fluid communication with saidindustrial fluid inlet and an outlet surface that is in fluidcommunication with said industrial fluid outlet, said inlet and outletsurfaces formed of sturdy corrugated screens that support and protect anintermediate fine mesh corrugated screen such that the filter elementwill retain contaminants carried by the industrial fluid as industrialfluid passes through said filter element; said filter assembly formedfrom three layers of metal mesh material, the outer and inner layersbeing sturdy screens having wire counts in the range of 40-60 wires perinch and the middle screen being a fine screen having openings in therange of 15-30 microns; said filter element including an endlessclosed-end portion edge and an endless open-end portion edge; a filtercollector received in said annular groove; said endlessclosed-endportion edge is bonded, along its entire extent, to the closed-end ofsaid hollow polymeric container and said endless-open end portion edgeis bonded along its entire extent to downwardly facing surface of saidfilter collector such that it surrounds said industrial fluid inletformed therein and isolates said industrial fluid inlet from saidindustrial fluid outlet; the material for bonding the endless closed-endportion edge and the endless open-end portion edge being a one partepoxy resin that can withstand operating temperatures betweenapproximately −40 degrees C. and 190 degrees C.; said open-end topmember being permanently secured to said hollow polymeric containerabout said open-end such that said filter element is permanently fixedto and unmovable to said hollow polymeric container; and a mountingattachment carried by said open-end top member for mounting saidrenewable filter to a source of industrial fluid to be filtered and to afilter cleaning mechanism.
 2. A renewable filter for filteringindustrial fluids as set forth in claim 1 and wherein the inventionfurther comprises: said filter assembly formed from three layers ofmetal mesh material, the outer and inner layers being sturdy screenshaving wire counts of about 50 wires per inch and the middle screenbeing a fine screen having openings of about 25 microns.
 3. A renewablefilter for filtering industrial fluids as set forth in claim 1, andfurther comprising: said polymeric top member having a dimension andshape such that there is interference between the polymeric top memberand the open-end of said hollow polymeric container, said interferencebeing sufficient to prevent said top member from being pressed to saidfully seated position, which interference is eliminated by plasticwelding allowing the polymeric top member to move to said fully seatedposition in said open-end of said hollow polymeric container.
 4. Arenewable filter for filtering industrial fluids as set forth in claim1, and further comprising: said filter element being a frusta-conicalshape.